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Posted to issues@iceberg.apache.org by GitBox <gi...@apache.org> on 2019/11/12 21:17:31 UTC
[GitHub] [incubator-iceberg] shardulm94 commented on a change in pull
request #227: ORC column map fix
shardulm94 commented on a change in pull request #227: ORC column map fix
URL: https://github.com/apache/incubator-iceberg/pull/227#discussion_r345448631
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File path: orc/src/main/java/org/apache/iceberg/orc/ORCSchemaUtil.java
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@@ -0,0 +1,488 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.iceberg.orc;
+
+import com.google.common.base.Preconditions;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.Lists;
+import com.google.common.collect.Maps;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Optional;
+import java.util.concurrent.atomic.AtomicInteger;
+import org.apache.iceberg.Schema;
+import org.apache.iceberg.types.Type;
+import org.apache.iceberg.types.TypeUtil;
+import org.apache.iceberg.types.Types;
+import org.apache.orc.TypeDescription;
+
+/**
+ * Utilities for mapping Iceberg to ORC schemas.
+ */
+public final class ORCSchemaUtil {
+
+ private enum BinaryType {
+ UUID, FIXED, BINARY
+ }
+
+ private enum IntegerType {
+ TIME, INTEGER
+ }
+
+ private static class OrcField {
+ private final String name;
+ private final TypeDescription type;
+
+ OrcField(String name, TypeDescription type) {
+ this.name = name;
+ this.type = type;
+ }
+
+ public String name() {
+ return name;
+ }
+
+ public TypeDescription type() {
+ return type;
+ }
+ }
+
+ private static final String ICEBERG_ID_ATTRIBUTE = "iceberg.id";
+ private static final String ICEBERG_REQUIRED_ATTRIBUTE = "iceberg.required";
+
+ private static final String ICEBERG_BINARY_TYPE_ATTRIBUTE = "iceberg.binary-type";
+ private static final String ICEBERG_INTEGER_TYPE_ATTRIBUTE = "iceberg.integer-type";
+ private static final String ICEBERG_FIELD_LENGTH = "iceberg.length";
+
+ private static final Map<Type.TypeID, TypeDescription.Category> TYPE_MAPPING =
+ ImmutableMap.<Type.TypeID, TypeDescription.Category>builder()
+ .put(Type.TypeID.BOOLEAN, TypeDescription.Category.BOOLEAN)
+ .put(Type.TypeID.INTEGER, TypeDescription.Category.INT)
+ .put(Type.TypeID.TIME, TypeDescription.Category.INT)
+ .put(Type.TypeID.LONG, TypeDescription.Category.LONG)
+ .put(Type.TypeID.FLOAT, TypeDescription.Category.FLOAT)
+ .put(Type.TypeID.DOUBLE, TypeDescription.Category.DOUBLE)
+ .put(Type.TypeID.DATE, TypeDescription.Category.DATE)
+ .put(Type.TypeID.TIMESTAMP, TypeDescription.Category.TIMESTAMP)
+ .put(Type.TypeID.STRING, TypeDescription.Category.STRING)
+ .put(Type.TypeID.UUID, TypeDescription.Category.BINARY)
+ .put(Type.TypeID.FIXED, TypeDescription.Category.BINARY)
+ .put(Type.TypeID.BINARY, TypeDescription.Category.BINARY)
+ .put(Type.TypeID.DECIMAL, TypeDescription.Category.DECIMAL)
+ .build();
+
+ private ORCSchemaUtil() {}
+
+ public static TypeDescription convert(Schema schema) {
+ final TypeDescription root = TypeDescription.createStruct();
+ final Types.StructType schemaRoot = schema.asStruct();
+ for (Types.NestedField field : schemaRoot.asStructType().fields()) {
+ TypeDescription orcColumType = convert(field.fieldId(), field.type(), field.isRequired());
+ root.addField(field.name(), orcColumType);
+ }
+ return root;
+ }
+
+ private static TypeDescription convert(Integer fieldId, Type type, boolean isRequired) {
+ final TypeDescription orcType;
+
+ switch (type.typeId()) {
+ case BOOLEAN:
+ orcType = TypeDescription.createBoolean();
+ break;
+ case INTEGER:
+ orcType = TypeDescription.createInt();
+ orcType.setAttribute(ICEBERG_INTEGER_TYPE_ATTRIBUTE, IntegerType.INTEGER.toString());
+ break;
+ case TIME:
+ orcType = TypeDescription.createInt();
+ orcType.setAttribute(ICEBERG_INTEGER_TYPE_ATTRIBUTE, IntegerType.TIME.toString());
+ break;
+ case LONG:
+ orcType = TypeDescription.createLong();
+ break;
+ case FLOAT:
+ orcType = TypeDescription.createFloat();
+ break;
+ case DOUBLE:
+ orcType = TypeDescription.createDouble();
+ break;
+ case DATE:
+ orcType = TypeDescription.createDate();
+ break;
+ case TIMESTAMP:
+ orcType = TypeDescription.createTimestamp();
+ break;
+ case STRING:
+ orcType = TypeDescription.createString();
+ break;
+ case UUID:
+ orcType = TypeDescription.createBinary();
+ orcType.setAttribute(ICEBERG_BINARY_TYPE_ATTRIBUTE, BinaryType.UUID.toString());
+ break;
+ case FIXED:
+ orcType = TypeDescription.createBinary();
+ orcType.setAttribute(ICEBERG_BINARY_TYPE_ATTRIBUTE, BinaryType.FIXED.toString());
+ orcType.setAttribute(ICEBERG_FIELD_LENGTH, Integer.toString(((Types.FixedType) type).length()));
+ break;
+ case BINARY:
+ orcType = TypeDescription.createBinary();
+ orcType.setAttribute(ICEBERG_BINARY_TYPE_ATTRIBUTE, BinaryType.BINARY.toString());
+ break;
+ case DECIMAL: {
+ Types.DecimalType decimal = (Types.DecimalType) type;
+ orcType = TypeDescription.createDecimal()
+ .withScale(decimal.scale())
+ .withPrecision(decimal.precision());
+ break;
+ }
+ case STRUCT: {
+ orcType = TypeDescription.createStruct();
+ for (Types.NestedField field : type.asStructType().fields()) {
+ TypeDescription childType = convert(field.fieldId(), field.type(), field.isRequired());
+ orcType.addField(field.name(), childType);
+ }
+ break;
+ }
+ case LIST: {
+ Types.ListType list = (Types.ListType) type;
+ TypeDescription elementType = convert(list.elementId(), list.elementType(),
+ list.isElementRequired());
+ orcType = TypeDescription.createList(elementType);
+ break;
+ }
+ case MAP: {
+ Types.MapType map = (Types.MapType) type;
+ TypeDescription keyType = convert(map.keyId(), map.keyType(), true);
+ TypeDescription valueType = convert(map.valueId(), map.valueType(), map.isValueRequired());
+ orcType = TypeDescription.createMap(keyType, valueType);
+ break;
+ }
+ default:
+ throw new IllegalArgumentException("Unhandled type " + type.typeId());
+ }
+
+ // Set Iceberg column attributes for mapping
+ orcType.setAttribute(ICEBERG_ID_ATTRIBUTE, String.valueOf(fieldId));
+ orcType.setAttribute(ICEBERG_REQUIRED_ATTRIBUTE, String.valueOf(isRequired));
+ return orcType;
+ }
+
+ /**
+ * Convert an ORC schema to an Iceberg schema. This method handles the convertion from the original
+ * Iceberg column mapping IDs if present in the ORC column attributes, otherwise, ORC column IDs
+ * will be assigned following ORCs pre-order ID assignment.
+ *
+ * @return the Iceberg schema
+ */
+ public static Schema convert(TypeDescription orcSchema) {
+ List<TypeDescription> children = orcSchema.getChildren();
+ List<String> childrenNames = orcSchema.getFieldNames();
+ Preconditions.checkState(children.size() == childrenNames.size(),
+ "Error in ORC file, children fields and names do not match.");
+
+ List<Types.NestedField> icebergFields = Lists.newArrayListWithExpectedSize(children.size());
+ AtomicInteger lastColumnId = new AtomicInteger(orcSchema.getMaximumId());
+ for (int i = 0; i < children.size(); i++) {
+ icebergFields.add(convertOrcToIceberg(children.get(i), childrenNames.get(i),
+ lastColumnId::incrementAndGet));
+ }
+
+ return new Schema(icebergFields);
+ }
+
+ /**
+ * Converts an Iceberg schema to a corresponding ORC schema within the context of an existing
+ * ORC file schema.
+ * This method also handles schema evolution from the original ORC file schema
+ * to the given Iceberg schema. It builds the desired reader schema with the schema
+ * evolution rules and pass that down to the ORC reader,
+ * which would then use its schema evolution to map that to the writer’s schema.
+ *
+ * Example:
+ * <code>
+ * Iceberg writer ORC writer
+ * struct<a (1): int, b (2): string> struct<a: int, b: string>
+ * struct<a (1): struct<b (2): string, c (3): date>> struct<a: struct<b:string, c:date>>
+ * </code>
+ *
+ * Iceberg reader ORC reader
+ * <code>
+ * struct<a (2): string, c (3): date> struct<b: string, c: date>
+ * struct<aa (1): struct<cc (3): date, bb (2): string>> struct<a: struct<c:date, b:string>>
+ * </code>
+ *
+ * @param schema an Iceberg schema
+ * @param originalOrcSchema an existing ORC file schema
+ * @return the resulting ORC schema
+ */
+ public static TypeDescription buildOrcProjection(Schema schema,
+ TypeDescription originalOrcSchema) {
+ AtomicInteger lastColumnId = new AtomicInteger(getMaxIcebergId(originalOrcSchema));
+ final Map<Integer, OrcField> icebergToOrc = icebergToOrcMapping("root",
+ originalOrcSchema, lastColumnId::incrementAndGet);
+ return buildOrcProjection(Integer.MIN_VALUE, schema.asStruct(), true, icebergToOrc);
+ }
+
+ private static TypeDescription buildOrcProjection(Integer fieldId, Type type, boolean isRequired,
+ Map<Integer, OrcField> mapping) {
+ final TypeDescription orcType;
+
+ switch (type.typeId()) {
+ case STRUCT:
+ orcType = TypeDescription.createStruct();
+ for (Types.NestedField nestedField : type.asStructType().fields()) {
+ String name = Optional.ofNullable(mapping.get(nestedField.fieldId()))
+ .map(OrcField::name)
+ .orElse(nestedField.name());
+ TypeDescription childType = buildOrcProjection(nestedField.fieldId(), nestedField.type(),
+ nestedField.isRequired(), mapping);
+ orcType.addField(name, childType);
+ }
+ break;
+ case LIST:
+ Types.ListType list = (Types.ListType) type;
+ TypeDescription elementType = buildOrcProjection(list.elementId(), list.elementType(),
+ list.isElementRequired(), mapping);
+ orcType = TypeDescription.createList(elementType);
+ break;
+ case MAP:
+ Types.MapType map = (Types.MapType) type;
+ TypeDescription keyType = buildOrcProjection(map.keyId(), map.keyType(), true, mapping);
+ TypeDescription valueType = buildOrcProjection(map.valueId(), map.valueType(), map.isValueRequired(),
+ mapping);
+ orcType = TypeDescription.createMap(keyType, valueType);
+ break;
+ default:
+ if (mapping.containsKey(fieldId)) {
+ TypeDescription originalType = mapping.get(fieldId).type();
+ Optional<TypeDescription> promotedType = getPromotedType(type, originalType);
+
+ if (promotedType.isPresent()) {
+ orcType = promotedType.get();
+ } else {
+ Preconditions.checkArgument(isSameType(originalType, type),
+ "Can not promote %s type to %s",
+ originalType.getCategory(), type.typeId().name());
+ orcType = originalType.clone();
+ }
+ } else {
+ if (isRequired) {
+ throw new IllegalArgumentException(
+ String.format("Field %d of type %s is required and was not found.", fieldId, type.toString()));
+ }
+
+ orcType = convert(fieldId, type, isRequired);
+ }
+ }
+
+ return orcType;
+ }
+
+ private static Map<Integer, OrcField> icebergToOrcMapping(String name, TypeDescription orcType,
+ TypeUtil.NextID nextID) {
+ Map<Integer, OrcField> icebergToOrc = Maps.newHashMap();
+ switch (orcType.getCategory()) {
+ case STRUCT:
+ List<String> childrenNames = orcType.getFieldNames();
+ List<TypeDescription> children = orcType.getChildren();
+ for (int i = 0; i < children.size(); i++) {
+ icebergToOrc.putAll(icebergToOrcMapping(childrenNames.get(i), children.get(i), nextID));
+ }
+ break;
+ case LIST:
+ icebergToOrc.putAll(icebergToOrcMapping("element", orcType.getChildren().get(0), nextID));
+ break;
+ case MAP:
+ icebergToOrc.putAll(icebergToOrcMapping("key", orcType.getChildren().get(0), nextID));
+ icebergToOrc.putAll(icebergToOrcMapping("value", orcType.getChildren().get(1), nextID));
+ break;
+ }
+
+ if (orcType.getId() > 0) {
+ // Only add to non-root types.
+ int icebergId = icebergID(orcType).orElseGet(nextID::get);
Review comment:
If the field id is missing, we seem to map based on the pre-order ID assignment. However these ids are completely different from Iceberg ids as they are not necessarily pre-order. This causes issues while reading the dataset as fields are not mapped correctly. IIRC in Avro at least, if the field id is missing for a particular field, we do not project the field. Should the same be done here?
(In Avro, if file has no ids at all, then we do name-based matching or we also have to option to use name mapping, but that can be done separately).
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